Sustainability, as a word and concept, has come to be a powerful rallying idea about how we humans should live on this planet. Yet there are just as many critics of the concept as there are supporters, and we will attempt to clarify what exactly the debate entails. We will do a deep dive into what we mean when we say ‘sustainability’ by learning about the about the many definitions, the origins and history, and political purpose of a sustainability lens. We will discuss deep vs shallow, weak vs strong, relative vs absolute sustainability, and the policy differences inherent in those distinctions. In our conversation, we will talk about how we think of sustainability in our own lives, and what relevance it has to our personal and community approaches to climate action.